Trust me, that's the speed during that period... if there's a large pause in the transfer then of course it will be a lower result. Over a larger transfer that delay has less and less of an effect on the speed. Plus, sizes over 6MB start for about 1/4 second before the timer to smooth that delay out. You should always trust the result from the larger size over smaller sizes. But the scores off smaller sizes can tell allot about the health of a connection as well.